Hygroscopic Balance in Pumpkin Seeds

Abstract

The commercial exploitation of pumpkin seeds, at the flour form toasted or to the production of oil, requires knowledge about the activity of water and equilibrium moistures. This study aimed to determine the equilibrium isotherms to the pumpkin seeds and describe the dynamics of the process upon its physicochemical quality. With the static method, the equilibrium isotherms were determined for different temperatures and activities of water (0.110 to 0.885 dry basis), provided conditions by the conditioner chamber of atmosphere, with the weighing of the samples until the constant mass. The hygroscopic balance of the seeds was directly proportional to the activity of water and decreased with increasing temperature, for the same value of water activity. The pumpkin seeds maintained the water volume (0.10) at the storage conditions (relative humidity 25 %). The modified Halsey model better represented the hygroscopicity of pumpkin seeds.

Qualidade do amendoim armazenado em diferentes embalagens

“…O manejo do produto em campo, na colheita e em processos pós-colheita, como secagem, aliado a presença de danos, oriundos do ataque de pragas e fungos, pode afetar a integridade da estrutura de sementes, provocando perdas de eletrólitos e proporcionando o desenvolvimento de patógenos (Saath et al, 2010;Ferreira et al, 2017). A integridade da membrana pode ser mensurada pela determinação de condutividade elétrica, que reflete a presença de íons em solução (Saath et al, 2017;Wenneck et al, 2020).…”

Water content in peanut seeds according to conditions of the storage environment

“…The equilibrium humidity of peanut seeds was influenced by temperature, relative humidity and the interaction of these factors, characteristic of the hygroscopic process (WENNECK et al, 2020;BUSTOS-VANEGAS et al, 2018). Considering the constant temperature, with variation of the relative humidity of the storage environment, it is possible to estimate the water content of the seeds under different conditions of relative humidity of the environment by mathematical models (Table 2).…”

“…Considering the constant temperature, with variation of the relative humidity of the storage environment, it is possible to estimate the water content of the seeds under different conditions of relative humidity of the environment by mathematical models (Table 2). The knowledge of the isothermal sorption models allows to obtain important information for the handling, associating preventive measures to the maintenance of the quality of the product (AGHAZADEH et al, 2021;WENNECK et al, 2020). The sorption process can alter the characteristics of the seed microstructure (MALLEK-AYADI et al, 2020), and the water content influences the thermodynamic properties of the product (CAMPOS et al, 2019).…”

“…Considering the mathematical model Chung-Pfost, equilibrium moisture of peanut seeds was estimated under different temperature and relative humidity conditions (Figure 2). Equilibrium moisture is stable as a function of temperature increase, as in quinoa seeds according to Bustos-Vanegas et al (2018) The relative humidity and temperature conditions that the product enters into equilibrium, regardless of the time to condition affect the integrity of the membrane structure, the commercial quality and the physiological potential of the product, reflecting the enzymatic and biochemical reactions that the conditions trigger in the seed (RESENDE; OLIVEIRA, SAATH et al, 2010;SAATH et al, 2021;ZIEGLER et al, 2017;WENNECK et al, 2020).…”

“…Considering that the changes in the thermodynamic properties of the product are related to changes in the environment, mainly water vapor, resulting in changes in the water content that influences enzymatic processes and the development of pathogens (BUSTOS-VANEGAS et al, 2018;CAMPOS et al, 2019;TUBBS et al, 2016;ZIEGLER et al, 2017). Understanding the dynamics of water in the seed becomes important to define strategies for preserving quality (AGHAZADEH et al, 2021;WENNECK et al, 2020).…”